Hiraku Kumamaru

Claims-based algorithms to identify stroke in a contemporary Medicare cohort had high positive predictive value and specificity, supporting their use as outcomes for etiologic and comparative effectiveness studies in similar populations. These inpatient algorithms are unsuitable for estimating stroke incidence because of low sensitivity.

The rate of CEA procedures decreased substantially during 2001 to 2008, as did surgeon past-year case-volume. The postprocedural mortality in Medicare beneficiaries was high compared with trial patients but somewhat improved over time. Those operated by lower past-year case-volume surgeons had increased mortality.

This study was funded by the Patient-Centered Outcomes Research Institute (ME-1309-06274). Kumamaru, Kohsaka, and Miyata are affiliated with the Department of Healthcare Quality Assessment at the University of Tokyo, which is a social collaboration department supported by National Clinical Database. The department was formerly supported by endowments from Johnson & Johnson K.K., Nipro, Teijin Pharma, Kaketsuken K.K., St. Jude Medical Japan, Novartis Pharma K.K., Taiho Pharmaceutical, W. L. Gore

The frailty algorithms were applicable to the Japanese system and could contribute to the identifications of enrollees at risk of long-term mortality or LTC use.

The number of databases available for clinico and pharmacoepidemiological research and the proportion of the population they cover are increasing in Japan. The differences in their characteristics mean that the appropriate database must be selected for a particular study purpose.

hdDRSs using historical data with dimension reduction and shrinkage was feasible, and improved confounding adjustment in two studies of newly marketed medications.